In order to reduce the size and power consumption of an optical transceiver and increase the capacity of the optical transceiver, it is important to dispose an optical device on a silicon substrate. Since an optical device formed on a silicon substrate may use an optical waveguide with a large relative refractive index difference, the optical device contributes to the reduction in size of an optical transceiver and may be integrated with an electronic circuit. Accordingly, one chip may include many optical transceivers.
In particular, the characteristic of a modulator that is an optical device has a large effect on the power consumption and size of an optical transceiver. Since a ring modulator has a small element size, a small modulation voltage, and a small optical loss, the ring modulator contributes to the reduction in size and power consumption of an optical transceiver.